Claims
- 1. A material suitable for a guest-host liquid crystal device comprising a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having the formula: ##STR34## wherein each of R.sub.A and R.sub.B is independently a group --CH.sub.2 Q.sup.1 wherein Q.sub.1 is an alkyl group having from 1 to 10 carbon atoms inclusive, and wherein each of the R groups is independently hydrogen or an alkyl group having from 1 to 4 carbon atoms inclusive.
- 2. A material as claimed in claim 1 and wherein at least one of the groups R.sub.A and R.sub.B is isobutyl.
- 3. A material as claimed in claim 1 and wherein the said compound is 4,8-diamino-2,6 di-isobutyl-1,5-dihydroxyanthraquinone, the groups R.sub.A and R.sub.B both being isobutyl groups.
- 4. A material as claimed in claim 1 and wherein the liquid crystal material includes one or more cyanobiphenyl liquid crystal compounds.
- 5. A material as claimed in claim 1 and wherein the liquid crystal material includes one or more cyanophenylcyclohexaneliquid crystal compounds.
- 6. A material as claimed in claim 1 and wherein the liquid crystal material is a nematic material suitable for a Fre edericksz effect or twisted nematic effect device.
- 7. A material as claimed in claim 1 and wherein the liquid crystal material is a long pitch cholesteric material suitable for a cholesteric-to-nematic phase change effects liquid crystal material formed of a mixture of a nematic material and a chiral material.
- 8. A material as claimed in claim 1 and wherein the pleochroic dye comprises a mixture of dyes of different color, at least one comprising a compound having the formula as defined in claim 1.
- 9. A liquid crystal electro-optical device comprising two electrically insulating substrates at least one of which is optically transparent, electrodes on the inner surfaces of the substrates and a film of dielectric material contained between the electrodes and the substrates, wherein the improvement comprises the dielectric material being material as claimed in claim 1.
- 10. A device as claimed in claim 9 and wherein the device is a cholesteric to nematic phase change effect device, the dielectric material being a long pitch cholesteric material.
Priority Claims (1)
Number |
Date |
Country |
Kind |
8024761 |
Jul 1980 |
GBX |
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a division of our earlier application Ser. No. 287,123, filed July 27, 1981, now U.S. Pat. No. 4,391,489.
US Referenced Citations (11)
Foreign Referenced Citations (13)
Number |
Date |
Country |
2104 |
May 1979 |
EPX |
25809 |
Apr 1981 |
EPX |
26004 |
Apr 1981 |
EPX |
38460 |
Oct 1981 |
EPX |
44893 |
Feb 1982 |
EPX |
2920730 |
Nov 1979 |
DEX |
3009974 |
Sep 1980 |
DEX |
3028593 |
Feb 1981 |
DEX |
3036853 |
Apr 1981 |
DEX |
3038372 |
May 1981 |
DEX |
2037803 |
Jul 1980 |
GBX |
2069518 |
Aug 1981 |
GBX |
2082196 |
Mar 1982 |
GBX |
Non-Patent Literature Citations (3)
Entry |
Abstracts of the Eighth International Liquid Crystal Conference, I-23 & I-24, Kyoto, Japan (Jun. 30-Jul. 4, 1980). |
Cognard, J., et al., Mol. Cryst. Liq. Cryst., vol. 70, pp. 1-19, (1981). |
Saeva, F. D., Xerox Discl. J., vol. 1, Nos. 9/10, pp. 61-62, (1976). |
Divisions (1)
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Number |
Date |
Country |
Parent |
287123 |
Jul 1981 |
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